This invention relates to rain gauges. More particularly, it relates to a dynamic rain gauge assembly which is responsive to the velocity and direction of rain fall such that the rain gauge assembly is capable of accurately collecting and measuring rain fall under dynamic weather conditions.
Rain gauges have long been used as part of man""s attempt to analyze and understand his environment. The most common form of rain gauge currently available is a graduated clear plastic or glass tube or cylinder which, when placed outdoors, does a fairly decent job of measuring rain fall. In fact, the clear plastic or glass graduated cylinder is very accurate in its measurement when rain fall is fairly perpendicular to the earth or ground. But because rain fall is typically the result of violent weather conditions in which the wind is blowing and the rain is driving in any direction but straight downwardly, the clear plastic or glass cylinder becomes quite inadequate for its intended purpose. Under those conditions, which can be quite dynamic, the driving wind and the concomitant rain comes from different directions and at different angles relative to the perpendicular. This rain, which is driven by the speed and direction of the wind, can also quickly and suddenly change directions under storm conditions. Under those storm conditions, the typical rain gauge is a very inaccurate way to measure rain fall. The reason for this is that the rain, when analyzed from a cross section of the dynamic perpendicular direction in which it falls, typically sees a circular opening to the rain collecting cylinder. To the contrary, the rain falling at a substantial angle to the perpendicular sees the circular opening to the graduated cylinder as anything but a perfect circle. Instead, it sees an ellipse. And the greater the angle at which the rain is being driven, the greater is this elliptical effect. That is, the square area of the ellipse as seen by the driving rain is proportionately smaller than the square area of the circular opening of the graduated cylinder as the angle relative to the perpendicular becomes greater.
A number of devices have been constructed in an attempt to take a rain gauge-like device and somehow try to keep it pointed in the direction of the driving rain. And they attempt to do this while the rain gauge-like device is filling the device. See, for example, U.S. Pat. No. 5,531,114 issued to Frager and U.S. Pat. No. 3,826,135 issued to Hollmann. In the experience of this inventor, such devices have a fundamental problem. As the rain gauge begins to fill, it is doomed to fail as an accurate measuring device because the weight of the rain which is collected tends to weigh down and defeat the wind direction devices which are also incorporated in those devices. Also in the experience of this inventor, it is critical to the accurate performance of the device to separate the rain collecting and the wind reacting elements of the device from one another. Accordingly, it is an object of this invention to provide a rain gauge assembly which accurately collects and measures rain fall regardless of the direction or velocity of the driving rain. It is another object of this invention to provide such an assembly which separates the rain collecting and the wind collecting elements of the assembly. It is yet another object of this invention to provide a rain gauge assembly which utilizes a minimal number of elements to accomplish the intended result. It is still another object to provide such an assembly which is easy to assemble and use.
The present invention has obtained these objects. It provides for a rain gauge assembly having a collection cylinder situated within a vertical support housing. The lowermost portion of the collection cylinder comes to a point which rests upon the bottommost surface of the support housing. The uppermost portion of the collection cylinder is supported by the uppermost portion of the support housing. Connected to the uppermost portion of the collection cylinder is a flexible connector which is, in turn, connected to a collector and a collector funnel. Affixed to the collector is a wind deflector support arm. The wind deflector support arm is attached to a vertical deflecting fin and a horizontal deflecting fin. The vertical and horizontal fins are situated in perpendicular planes for reacting to both wind direction and wind velocity, respectively. The foregoing and other features of the present invention will be further apparent from the detailed description which follows.